I've got my money's worth from a Spin Doctor-level stand over the last 15 years. Like OP, I don't build many, but I've re-trued a lot of wheels. $4-5 a year and I get to sit in front of the TV in air conditioned or heated room -- totally worth it.

Make sure the stand matches the axle type you'll be working on. Anything will work with standard quick release axles, but you might be careful if you're looking at very wide wheels with through axles.